Difference between revisions of "User:Cheepicus"

Revision as of 11:54, 1 August 2010

Fluids (water and magma) in Dwarf Fortress normally flow in a predictable way, "spilling" and spreading out, and flowing down. However, there is another way these fluids can move--pressure--which can be mystifying, unexpected, and Fun.

It is tempting to think of pressure in terms of bodies of fluid being 'pressurized' or 'pushed around' by pressure, but it is more useful to think of pressure as something that happens to a single individual "block" of fluid, moving it to a possibly distant location, like teleportation.

Creating Pressure

A single "block" of fluid will try to move by pressure when it is created or moved one of the following ways, *and the target space is already full (7/7) of the fluid*:

1) Water falling down a level. 2) A pump pumping water OR magma up to a level. 3) Water being created, moving onto the map, as in the source of a river or stream on the map's edge.

Moving via Pressure

When, as above, the moving block of fluid wants to move or be created by the target space is full, pressure kicks in and attempts to teleport the fluid somewhere else connected to the body of fluid.

So the game looks for a path to move the block. This path: 1) Will only travel through spaces full (7/7) of the fluid, 2) Can span Z-levels, but 3) Only travels orthogonally (north, south, east, west, favoring those before going down, and possible going up), and 4) Will *not* go up above the Z-level of the space *into which it was originally trying to move*.

The search for this path can fail, in which case the movement doesn't happen; the water does not fall, the pump does not pump, and new water is not created.

Behavior

Given the above, some strange behaviors emerge:

Water will flow around a U-bend, but magma will not

This is because falling magma does not create pressure.

Pumps can make magma move via pressure

This is just the way it is.

Diagonal motions of water "remove pressure"

This is because the path to find a place to move fluid by pressure will not go diagonally.

Water falling from level Z can move via pressure only up to level Z+1

That's because it's trying to move into the space on level Z+1, so that is the starting level of the pressure move.

A pump on level Z will fill up to level Z

That's because the fluid is trying to move to the output of the pump, which is on level Z.

Water flowing through a U-bend equalizes with the far side lower, or exactly even

That's because the last bit of water is trying to fall down to level Z, and pressure cannot move it back up to the level it's falling from.

A river tapped for water will fill a reservoir up to one Z-level lower than the river source...

This is because when a river is flowing normally, water that is created on the edge will move via pressure far downstream to fill some of the open space where the water is draining. Pressure will find these spots before it paths down through any U-bends.

... but if the river is dammed, it will fill the reservoir up to the Z-level of the river

When the river is dammed, the usual open space downstream is gone, so pressure will now start to look downwards for paths that can possibly lead to your reservoir system, and back up to the Z-level of the river. Any pressure you see in your reservoir system *before* that is due to falling water pressure, not pressure from the source of the river.

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-I am a player of moderate experience. I've been trying to branch out more lately.
+Fluids (water and magma) in Dwarf Fortress normally flow in a predictable way, "spilling" and spreading out, and flowing down. However, there is another way these fluids can move--pressure--which can be mystifying, unexpected, and Fun.
-== Starting Build ==
+It is tempting to think of pressure in terms of bodies of fluid being 'pressurized' or 'pushed around' by pressure, but it is more useful to think of pressure as something that happens to a single individual "block" of fluid, moving it to a possibly distant location, like teleportation.
-For a long time my starting build has been pretty stable.
+== Creating Pressure ==
-=== Dwarfs ===
+A single "block" of fluid will try to move by pressure when it is created or moved one of the following ways, *and the target space is already full (7/7) of the fluid*:
-* Miner 5 / Appraiser 1 / Persuader 1 / Negotiator 1 / Intimidator 1 / Judge of Intent 1
+) Water falling down a level.
-* Miner 5 / Brewer 5
+) A pump pumping water OR magma up to a level.
-* Miner 5 / Cook 5
+) Water being created, moving onto the map, as in the source of a river or stream on the map's edge.
-:The early mining crew. They give up mining with the first migrants.
-* Mechanic 5 / Siege Engineer 5
-* Carpenter 5 /  Stonecrafter 5
-* Mason 5 / Architect 5
-* Grower 5 / Armorsmith 5
-=== Equipment ===
+== Moving via Pressure ==
-* 1 anvil, 0 axes, 0 cats, 3 picks.
+When, as above, the moving block of fluid wants to move or be created by the target space is full, pressure kicks in and attempts to teleport the fluid somewhere else connected to the body of fluid.
-* 2-4 dogs. 1 cat.
-* 12ish plump helmet spawn, 1 dimple cup spawn, 5 of each other seed.
-* 1 of each food costing 2 or 4.
-* Scads of wood. Often 41, because 41+wagon = 44 = 4 x 11, which is 4 rows of the 11x11 area I dig out first.
-== Fortress Ideas ==
+So the game looks for a path to move the block. This path:
+) Will only travel through spaces full (7/7) of the fluid,
+) Can span Z-levels, but
+) Only travels orthogonally (north, south, east, west, favoring those before going down, and possible going up), and
+) Will *not* go up above the Z-level of the space *into which it was originally trying to move*.
-My typical fortress has one central shaft with everything sprouting off of that. Sometimes this is too boring and I want to try something else.
+The search for this path can fail, in which case the movement doesn't happen; the water does not fall, the pump does not pump, and new water is not created.
-One thing I have been sort of playing with is "1 room per purpose", rather than "dig out a big space and cram stuff in it."
+== Behavior ==
-=== City fortress ===
+Given the above, some strange behaviors emerge:
-The buildings are all on one z-level far underground, laid out with a grid of streets. No surface defenses; invaders must be allowed to march right down to the z-level of the city. (Don't piss off the humans!) Ideally buildings and areas are 'guild related' with 100% assigned beds and dining rooms, with mechanics next to other mechanics, and so on.
-I've done a couple fortresses along these lines. Fun, and I don't think I'm done with it yet. Would like to have the city have rain, have not quite worked out how to have water falling gently over a large xy area. Probably I can do this with a "pachinko machine" apparatus above the city, where water streams into a central hole and then is sieved out. Another method would be a single big room, filled by a reservoir to a shallow depth; the floor of the room has a shitload of hatches, which are linked to repeaters on different syncs, so that sometimes they are open and sometimes not. Super bonus cool would be for the rain amount to vary over time (extra credit; to match game seasons) without any manual input from dorfs).
+=== Water will flow around a U-bend, but magma will not ===
+This is because falling magma does not create pressure.
-=== Roguelike fortress ===
+=== Pumps can make magma move via pressure ===
-By this I mean a fortress whose useful areas are dug in rooms, which are joined up by corridors. The corridors are dug ad hoc to join up rooms, vs. the concept of adding rooms onto a skeleton of corridors. This would be a deliberately inefficient design.
+This is just the way it is.
-=== Narrow Tower ===
+=== Diagonal motions of water "remove pressure" ===
-Making a challenge out of my normal method, the whole fortress is vertically aligned 11x11 chambers. Exploratory mining and plumbing are allowed, but all buildings must be in the 11x11 footprint.  Obviously having a cliffside would help.
+This is because the path to find a place to move fluid by pressure will not go diagonally.
-== Previous Fortresses ==
+=== Water falling from level Z can move via pressure only up to level Z+1 ===
+That's because it's trying to move into the space on level Z+1, so that is the starting level of the pressure move.
-=== Systembooks and Plaitbust, Underground Cities ===
+=== A pump on level Z will fill up to level Z ===
+That's because the fluid is trying to move to the output of the pump, which is on level Z.
-Had some fun with underground cities with buildings laid out on a grid, avoiding the use of z-levels as much as possible.
+=== Water flowing through a U-bend equalizes with the far side lower, or exactly even ===
+That's because the last bit of water is trying to fall down to level Z, and pressure cannot move it back up to the level it's falling from.
-[http://mkv25.net/dfma/map-7087-systembooks Systembooks at DFMA]
+=== A river tapped for water will fill a reservoir up to one Z-level lower than the river source... ===
+This is because when a river is flowing normally, water that is created on the edge will move via pressure far downstream to fill some of the open space where the water is draining. Pressure will find these spots before it paths down through any U-bends.
-[http://mkv25.net/dfma/map-7158-plaitbust Plaitbust at DFMA]
+=== ... but if the river is dammed, it will fill the reservoir up to the Z-level of the river ===
+When the river is dammed, the usual open space downstream is gone, so pressure will now start to look downwards for paths that can possibly lead to your reservoir system, and back up to the Z-level of the river.  Any pressure you see in your reservoir system *before* that is due to falling water pressure, not pressure from the source of the river.
-Plaitbust got up to 289 dorfs, my largest fortress so far.
-=== Reignlens, Guild Outpost ===
-Here I wanted to make a fortress centered on ONE universal stockpile. (With no dump reclaim, bin max 0, but separate stinky-item stockpiles allowed.) Around the stockpile would be a ring of guild structures where each dwarf has quarters and dining facilities personally assigned (except peasants).
-This is in some sense the opposite of my usual fortress design, where there's a big undifferentiated apartment block, then a big open room for workshops and stockpiles with a lot of time spent worrying about stockpile size and placement.
-[http://mkv25.net/dfma/map-7063-reignlensoutpost Reignlens at Map Archive]
-I didn't know the maximum stockpile size is 31x31, which meant that after THE stockpile filled up, it was like having no stockpile. Organizing by guild was annoying by first but quickly became fun.
-Not really an inspiring fortress but a fun little mini-challenge for me.
-=== Targetarch, Sand Fortress ===
-[[Image:TargetArch.png|thumb|left|200px|On embark.]][[Image:TargetArchOops.png|thumb|left|200px|Oops.]]
-A sand/magma/aquifer fortress, was amusingly saved from flooding (embarrassingly noobish mistake) but then became boring. Really if I want to play a no stone-layer fortress, I'll probably have to forgo magma, or do it as a conduct.
-Centering the fortress around the top room of a magma pipe is still interesting to me. Or maybe it's that flooding them is such fun.